589 research outputs found
Optimal Beamforming for Gaussian MIMO Wiretap Channels with Two Transmit Antennas
A Gaussian multiple-input multiple-output wiretap channel in which the
eavesdropper and legitimate receiver are equipped with arbitrary numbers of
antennas and the transmitter has two antennas is studied in this paper. Under
an average power constraint, the optimal input covariance to obtain the secrecy
capacity of this channel is unknown, in general. In this paper, the input
covariance matrix required to achieve the capacity is determined. It is shown
that the secrecy capacity of this channel can be achieved by linear precoding.
The optimal precoding and power allocation schemes that maximize the achievable
secrecy rate, and thus achieve the capacity, are developed subsequently. The
secrecy capacity is then compared with the achievable secrecy rate of
generalized singular value decomposition (GSVD)-based precoding, which is the
best previously proposed technique for this problem. Numerical results
demonstrate that substantial gain can be obtained in secrecy rate between the
proposed and GSVD-based precodings.Comment: Accepted for publication in IEEE Transactions on Wireless
Communication
Achieving secrecy without knowing the number of eavesdropper antennas
The existing research on physical layer security commonly assumes the number
of eavesdropper antennas to be known. Although this assumption allows one to
easily compute the achievable secrecy rate, it can hardly be realized in
practice. In this paper, we provide an innovative approach to study secure
communication systems without knowing the number of eavesdropper antennas by
introducing the concept of spatial constraint into physical layer security.
Specifically, the eavesdropper is assumed to have a limited spatial region to
place (possibly an infinite number of) antennas. From a practical point of
view, knowing the spatial constraint of the eavesdropper is much easier than
knowing the number of eavesdropper antennas. We derive the achievable secrecy
rates of the spatially-constrained system with and without friendly jamming. We
show that a non-zero secrecy rate is achievable with the help of a friendly
jammer, even if the eavesdropper places an infinite number of antennas in its
spatial region. Furthermore, we find that the achievable secrecy rate does not
monotonically increase with the jamming power, and hence, we obtain the
closed-form solution of the optimal jamming power that maximizes the secrecy
rate.Comment: IEEE transactions on wireless communications, accepted to appea
A Survey of Physical Layer Security Techniques for 5G Wireless Networks and Challenges Ahead
Physical layer security which safeguards data confidentiality based on the
information-theoretic approaches has received significant research interest
recently. The key idea behind physical layer security is to utilize the
intrinsic randomness of the transmission channel to guarantee the security in
physical layer. The evolution towards 5G wireless communications poses new
challenges for physical layer security research. This paper provides a latest
survey of the physical layer security research on various promising 5G
technologies, including physical layer security coding, massive multiple-input
multiple-output, millimeter wave communications, heterogeneous networks,
non-orthogonal multiple access, full duplex technology, etc. Technical
challenges which remain unresolved at the time of writing are summarized and
the future trends of physical layer security in 5G and beyond are discussed.Comment: To appear in IEEE Journal on Selected Areas in Communication
Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey
This paper provides a comprehensive review of the domain of physical layer
security in multiuser wireless networks. The essential premise of
physical-layer security is to enable the exchange of confidential messages over
a wireless medium in the presence of unauthorized eavesdroppers without relying
on higher-layer encryption. This can be achieved primarily in two ways: without
the need for a secret key by intelligently designing transmit coding
strategies, or by exploiting the wireless communication medium to develop
secret keys over public channels. The survey begins with an overview of the
foundations dating back to the pioneering work of Shannon and Wyner on
information-theoretic security. We then describe the evolution of secure
transmission strategies from point-to-point channels to multiple-antenna
systems, followed by generalizations to multiuser broadcast, multiple-access,
interference, and relay networks. Secret-key generation and establishment
protocols based on physical layer mechanisms are subsequently covered.
Approaches for secrecy based on channel coding design are then examined, along
with a description of inter-disciplinary approaches based on game theory and
stochastic geometry. The associated problem of physical-layer message
authentication is also introduced briefly. The survey concludes with
observations on potential research directions in this area.Comment: 23 pages, 10 figures, 303 refs. arXiv admin note: text overlap with
arXiv:1303.1609 by other authors. IEEE Communications Surveys and Tutorials,
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